Stacked battery and method of producing the same

Abstract

A stacked battery includes a square battery element in which a tabular positive electrode, a separator and a tabular negative electrode are laminated, wherein: one side of the battery element is a terminal connection section pulled-out surface, which is provided on both the positive and negative electrodes and where a plate-like positive-electrode terminal connection section and a plate-like negative-electrode terminal connection are both pulled out; projection surfaces, which are generated by vertically projecting the positive-electrode terminal connection section and the negative-electrode terminal connection section onto surfaces extending from the positive and negative electrodes, do not cross each other; a surface of the positive electrode and a surface of the negative electrode, which are facing each other, are different in area; each electrode is disposed so that an entire projection portion, which is generated by projecting the small-area electrode onto a surface of a large-area electrode that faces the small-area electrode, is positioned on the large-area electrode; on a separator, a bumping section is provided to limit movements of positive and negative electrodes as a positive-electrode end surface and a negative-electrode end surface hit the bumping section; and as for the bumping section, separators are joined by a crease or joining section of adjacent separators among separators disposed on electrode surfaces.

Description

TECHNICAL FIELD[0001]The present invention relates to a battery sealed with a film casing material, and to a stacked battery in which an opening of a battery element, which is made by laminating a predetermined number of tabular positive and negative electrodes along with separators, is sealed with a film casing material.BACKGROUND ART[0002]For a portable phone and other portable devices that use batteries, a lithium ion battery having a large charge and discharge capacity and the likes are widely used. Moreover, for use in an electric vehicle, electric bicycle, electric tool, electric power storage and the like, what is required is a secondary battery that has a large charge and discharge capacity and is highly efficient.[0003]For such a high-power battery, in order to increase energy density per volume or mass of the battery, as a casing container of the battery, the use of a film casing material that can be made thinner, instead of a ferrous material or a material made of aluminu...

AI Technical Summary

Benefits of technology

The present invention solves the problem of decreased battery performance in a stacked battery caused by the negative electrode moving away from its original position inside the battery. The invention provides a battery with a sealed opening using a film casing material that can maintain the positional relationship between the positive and negative electrodes, even when subjected to excessive shocks and vibrations. Additionally, the invention provides a stacked battery that enables the positions of both positive and negative electrodes to be determined with high accuracy during the assembly process.

Problems solved by technology

However, depending on a friction coefficient between layers of the positive and negative electrodes and separators and how a gas is generated inside the battery, the pushing force of the atmospheric pressure may not work effectively.

However, as the positive and negative electrodes move away from original positions, the relative positional relationship between the positive and negative electrodes becomes distorted, possibly leading to a decrease in battery performance and other problems.

As a result, the problem is that the distance between the electrodes increases, and that the electric resistance between the electrodes increases.

However, in a battery that has a large number of positive and negative electrodes laminated and a large charge and discharge capacity, a welding portion of a separator needs to significantly stick out.

As a result, the problem is that a space emerges between a battery element and a casing material, resulting in a decrease in volume efficiency.

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